Keyword: beam-loading
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MOPMW001 A New Buncher for the ESRF Linac Injector linac, electron, cavity, gun 389
 
  • A.S. Setty, A.S. Chauchat, D. Jousse
    Thales Communications & Security (TCS), Gennevilliers Cedex, France
  • H. Delamare, J. Jacob, B. Ogier, T.P. Perron, E. Rabeuf, C. Richard, V. Serrière, R. Versteegen
    ESRF, Grenoble, France
 
  The electron linac was designed to be able to deliver more than 2.5 A in less than 2 ns at 200 MeV within an energy spread of 1% for positrons production at ESRF *. The 200 MeV electron linac was commissioned in 1991. A new gun, a cleaner, a pre-buncher cavity and 4 shielded lenses were tested and installed on the injector in 2008 **. Then, a new Buncher for the ESRF electron linac injector was manufactured and commissioned in 2015. Meanwhile, some new settings were performed to reduce the energy spread for both cases: the long pulse mode and the short pulse mode. The simulations and measurements will be presented.
* D. Tronc et Al. "Electron injector for light source", Proc. EPAC88, Italy, Rome, June 1988.
** T. Perron et Al. "New preinjector for the ESRF booster", Proc. EPAC08, Italy, Genoa, June 2008.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW001  
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MOPOR013 The PS 10 MHz High Level RF System Upgrade cavity, feedback, impedance, network 622
 
  • G. Favia, H. Damerau, V.D. Desquiens, S. Energico, M. Morvillo, D. Perrelet, C. Rossi
    CERN, Geneva, Switzerland
 
  In view of the upgrade of the injectors for the High Luminosity LHC, significantly higher bunch intensity is required for LHC-type beams. In this context an upgrade of the main accelerating RF system of the Proton Synchrotron (PS) is necessary, aiming at reducing the cavity impedance which is the source of longitudinal coupled-bunch oscillations. These instabilities pose as a major limitation for the increase of the beam intensity as planned after LS2. The 10 MHz RF system consists in 11 ferrite loaded cavities, driven by tube-based power amplifiers for reasons of radiation hardness. The cavity-amplifier system is equipped with a wide-band feedback that reduces the beam induced voltage. A further reduction of the beam loading is foreseen by upgrading the feedback system, which can be reasonably achieved by increasing the loop gain of the existing amplification chain. This paper describes the progress of the design of the upgraded feedback system and shows the results of the tests on the new amplifier prototype, installed in the PS during the 2015-16 technical stop. It also reports the first results of its performance with beam, observed in the beginning of the 2016 run.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR013  
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TUPOW021 Beam Dynamics Optimization and Future Plans for LUE-200 Linac Upgrade simulation, klystron, bunching, linac 1788
 
  • S.M. Polozov, T.V. Bondarenko
    MEPhI, Moscow, Russia
  • A.V. Butenko, V. Kobets, A.P. Sumbaev
    JINR, Dubna, Moscow Region, Russia
 
  The IREN facility (Intense Resonance Neutron Source) is now been tested and upgraded in JINR. The linear electron accelerator LUE-200 is used to generate intense fluxes of resonant photo-neutrons. Linac should deliver up to 200 MeV electron beam with 1 A or more current in 100 - 200 ns pulses. It consists of electron source, LEBT including buncher and two main accelerating sections (only one is installed up to now). Test operations shows that beam loading sufficiently influences the output beam parameters and beam energy after first section decreases from planned 55-60 MeV to 35 MeV. The buncher doesn't provide an efficient beam bunching also and beam recapturing by main section due to this is very low. Dynamics of the electron beam for traveling wave S-band linac LUE-200 was studied by numerical simulations. In report results of beam dynamics simulation and optimization taking into account beam loading discuss, parameters for new more effective buncher presents and first results of such buncher development shows.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW021  
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TUPOW043 Electron Beam Dynamics Studies for ELI-NP GBS Linac electron, linac, operation, photon 1857
 
  • A. Giribono, F. Cardelli, L. Palumbo, L. Piersanti
    University of Rome La Sapienza, Rome, Italy
  • D. Alesini, A. Gallo, C. Vaccarezza, A. Vannozzi
    INFN/LNF, Frascati (Roma), Italy
  • A. Bacci, C. Curatolo, I. Drebot, V. Petrillo, A.R. Rossi, L. Serafini
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • G. Campogiani
    Rome University La Sapienza, Roma, Italy
  • F. Cardelli, L. Piersanti
    INFN-Roma1, Rome, Italy
  • L. Palumbo
    INFN-Roma, Roma, Italy
 
  The ELI-NP Gamma Beam System is an advanced gamma ray source based on the Compton back-scattering effect with unprecedented specifications of brilliance ( >1021), monochromaticity (0.5%) and energy tunability (0.2 - 19.5 MeV), presently under construction in Magurele-Bucharest (RO). Here the head-on collision is foreseen between an intense high power laser beam and a high brightness high quality electron beam with a maximum kinetic energy of 740 MeV. The electron beam dynamics analysis and control for the ELI-NP GBS Linac in the single and multi bunch mode have been investigated and are here illustrated.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW043  
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TUPOY007 Development of a Compact X-Band Electron Linac for Production of Mo-99/Tc-99m linac, electron, simulation, klystron 1917
 
  • J. Jang
    The University of Tokyo, Tokyo, Japan
  • M. Uesaka
    The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
  • M. Yamamoto
    Accuthera Inc., Kawasaki, Kanagawa, Japan
 
  In response to the need of alternatives to the exhausted research reactors supplying Mo-99/Tc-99m, we are developing a compact X-band electron linear accelerator (linac). As an initial step, beam dynamics simulations were performed and electron beams of 35 MeV and 9.1 kW were obtained. We expect that sixteen linacs having these beam parameters can cover the demand of Tc-99m radiopharmaceuticals in Japan. On the other hand, we found that the combination of X-band RF and high beam power can give rise to instability of beam loading. We will therefore adjust and optimize the beam power while keeping Mo-99 production efficiency as high as possible.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY007  
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WEPOR037 Beam Loading Effects in SSRF Storage Ring feedback, cavity, storage-ring, LLRF 2755
 
  • Y. Xia, Q. Chang, Z. Li, K. Xu, Zh.G. Zhang, S.J. Zhao, Y.B. Zhao, X. Zheng
    SINAP, Shanghai, People's Republic of China
 
  The beam current in the storage ring of Shanghai Synchrotron Radiation Facility (SSRF) is now normally 240 mA and projected to be raised to 300 mA. Heavy beam loading will be serious and associated Robinson instability needs to be compressed. In this paper, the beam loading effects in SSRF storage ring and methods to increase current limit will be discussed. .  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR037  
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WEPOR058 Preliminary Study for the HLS Variable Pulse Length Storage Ring by Two Harmonic Cavities cavity, storage-ring, synchrotron, electron 2802
 
  • T. Zhang, W. Li, L. Shang, L. Wang, C.-F. Wu
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  The 4th harmonic cavity is successfully used in HLS II to increase the beam lifetime and suppress the beam instability now. At the future, a scheme of the two higher harmonic cavities may be applied in Hefei light source for a variable electron pulse length storage ring (HLS VSR). With optimal RF system parameters, 45 ps long bunches and 6 ps short bunches may be stored simultaneously in the HLS storage ring. The ratio of the bunch number for 45 ps to the one for 6 ps is 1:2. Particle tracking calculations are performed to simulate the longitudinal phase space of the new system and to track the process of shortening bunches with Elegant Software. Moreover, a tracking simulation code for RF systems is developed in MALAB to study transient beam loading which affects bunch length, phase stability, and longitudinal muti-bunch oscillation for different fill patterns. In the end, the preliminary design of the two harmonic cavities for longitudinal bunch focusing is given.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR058  
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WEPOW037 Bunch Length Measurements with Passive Harmonic Cavities for Non-uniform Fill Patterns in a 100 MHz RF System simulation, storage-ring, cavity, feedback 2918
 
  • T. Olsson, S.C. Leemann, P. Lilja
    MAX IV Laboratory, Lund University, Lund, Sweden
 
  The MAX IV facility includes two storage rings operated at 1.5 GeV and 3 GeV, which are both designed to operate with a uniform, multibunch fill pattern. Both rings have a 100 MHz RF system and employ passive harmonic cavities to damp instabilities and increase Touschek lifetime. Recently, a discussion on timing modes at the MAX IV storage rings has been initiated by the user community. Creating opportunities for timing experiments implies operating the rings with other fill patterns than the planned multibunch mode. Such operation can, however, cause transient effects in the passive harmonic cavities which affect the performance of the machine. It is therefore of interest to study the effect on the beam when operating with non-uniform fill patterns. This paper presents bunch length measurements at the 100 MHz MAX II storage ring for fill patterns with gaps. The purpose of the measurements was to evaluate the employed measurement method and simulation codes for future studies of various alternate fill patterns in the MAX IV storage rings.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW037  
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WEPOY002 A Time Domain Analysis Method for RF Noise simulation, cavity, experiment, LLRF 2994
 
  • L. Lin, B. Du, G. Huang, Y.T. Liu
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  A time domain analysis method is developed for the calculation of the longitudinal oscillations caused by the RF noise in the storage ring. This method is based on the impulse response model, and it could calculates the change of transient field caused by beam oscillation and RF noise turn by turn. By means of discrete spectrum analysis, the spectrum of the beam is obtained. According to this analysis method, we developed a simulation pro-gram. The synchronous oscillation of the excited by high RF source with a phase modulation is predicted in this program, and the corresponding experimental measure-ments are carried out on HLS II. The fitting results are in agreed with the experimental measurements.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY002  
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THPMR025 Simulation of Beam Behavior Caused by Odd Harmonics of Beam Loading in J-PARC RCS simulation, cavity, acceleration, resonance 3443
 
  • M. Yamamoto, M. Nomura, T. Shimada, F. Tamura
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • K. Hara, K. Hasegawa, C. Ohmori, M. Toda, M. Yoshii
    KEK, Tokai, Ibaraki, Japan
 
  The J-PARC RCS accelerates 2 bunches at the harmonic number 2. The major Fourier component of the beam current is even harmonics. However, the odd harmonics grow under some conditions even though they are very small amplitude at the beginning. We describe the the particle tracking simulation results for the odd harmonic beam loading effect in the RCS.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR025  
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THPOR031 Beam-Loading Effect on Breakdown Rate in High-Gradient Accelerating Structures klystron, linac, experiment, controls 3848
 
  • F. Tecker, T. Argyropoulos, N. Catalán Lasheras, R. Corsini, A. Degiovanni, D. Gamba, J. Giner Navarro, A. Grudiev, G. McMonagle, J.L. Navarro Quirante, R. Rajamaki, E. Senes, I. Syratchev, B.J. Woolley, W. Wuensch
    CERN, Geneva, Switzerland
  • T. Argyropoulos, J. Giner Navarro
    IFIC, Valencia, Spain
  • A. Degiovanni, J.L. Navarro Quirante
    ADAM, Geneva, Switzerland
  • D. Gamba
    JAI, Oxford, United Kingdom
  • R. Rajamaki
    Aalto University, School of Science and Technology, Aalto, Finland
  • E. Senes
    Torino University, Torino, Italy
  • J. Tagg
    National Instruments Switzerland, Ennetbaden, Switzerland
 
  The Compact Linear Collider (CLIC) study for a future electron-positron collider with a center-of-mass energy up to 3 TeV aims for an accelerating gradient of 100 MV/m. The gradient is limited by RF breakdowns, and the luminosity requirements impose a limit on the admissible RF breakdown rate. RF testing of 12 GHz structure prototypes has shown that gradients in excess of 100 MV/m can be reached with the required breakdown rate. However at CLIC, the structures will be operated with significant beam-loading, modifying the field distribution inside. The effect of the beam-loading must be well understood but has not been previously measured. The commissioning and operation of an experiment to measure the effect of beam-loading on breakdown rate and the measurement results are presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR031  
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